Wheelchair seat and backrest construction

Abstract

A wheelchair backrest and seat is mounted on chair tubes that form part of the wheelchair frame, using suspension hooks adapted to partially surround the chair tubes. Special abutment devices are slidably mounted on the chair tubes to prevent the hooks from shifting on the chair tubes. Each abutment device has a latch element that can be projected over the associated hook to prevent the hook from movement away from the chair tube.

What is claimed: 
     
       1. In a wheel chair having two parallel chair tubes and a backrest locatable between said chair tubes; the improvement comprising two hooks extending from said backrest over each of said chair tubes, two rows of hook anchorages on said backrest, each row comprising at least three anchorages; said hooks being selectively mounted at different ones of said anchorages, to vary the inclination of the back rest, each anchorage comprising an angle member having a first leg securable to the backrest and a second leg securable to an associated hook. 
     
     
       2. In a wheelchair having two parallel upstanding chair tubes, and a backrest supportable between said chair tubes; the improvement comprising: said backrest comprising a concave rigid shell having a concave front surface, and a cushion mounted on said concave front surface;   two hooks extending from said rigid shell partially around each upstanding chair tube;   two abutments slidable on each chair tube to prevent said hooks from shifting along said chair tubes, and a latch element projectible from each abutment over an associated hook, whereby said hooks are prevented from displacement away from the chair tubes;   said rigid shell having two rows of hook anchorages;   each of said rows comprising at least three anchorages;   said hooks being selectively mounted at different ones of said anchorages to vary the inclination of said backrest; and   wherein each of said anchorages comprises an angle member having a first leg securable to said rigid shell and a second leg securable to an associated hook.     
     
     
       3. The improvement of claim 2, wherein there are four anchorages in each row of anchorages. 
     
     
       4. The improvement of claim 2, and further comprising an adjustable attachment means joining each said hook to the second leg of each associated angle member; each said attachment means comprising a first linear slot (49) in each respective second leg, and first and second threaded fasteners (50, 51) extending from each respective hook through the associated linear slot;   each hook having a second slot extending transverse to said first linear slot in intersecting relationship;   each said second threaded fastener extending through said second transverse slot so that said hook is swingably adjustable around said first threaded fastener.   
     
     
       5. In a wheelchair having two parallel upright chair tubes, a backrest locatable between said chair tubes, and two parallel horizontal chair tubes; the improvement comprising a generally planar rigid metal seat plate, and connector means for adjustably connecting said metal seat plate to said horizontal chair tubes so that said seat plate has a horizontal disposition between said chair tubes; said seat plate having a front edge, two side edges, and a rear edge; said seat plate having a series of integral shallow reinforcing channels extending from said front edge to said rear edge parallel to said side edges; each of said reinforcing channels having a height dimension and a width dimension; the width dimension of each of said reinforcing channels being appreciably greater than the height dimension; each of said reinforcing channels having an arcuate cross section offset upwardly from the plane of said seat plate; the height dimension of each said reinforcing channel being approximately the same as the thickness of said seat plate; said connector means comprising a first set of slots (80) in said seat plate proximate to the front edge of said seat plate and a second set of slots (80) in said seat plate proximate to the rear edge of said seat plate, each of said slots extending parallel to the front and rear edges of said seat plate; said connector means further comprising four angle members (76) adjustably attached to said seat plate at said slots; each of said angle members having a horizontal leg (77) adjustably attached to said plate via one of said slots, and a downwardly extending vertical leg (79); said connector means further comprising a hook (34) adjustably attached to the vertical leg of each of said angle members; said hooks extending upwardly above the plane of said seat plate for partial encirclement around said horizontal chair tubes.